Trouble with private portion of Classes

Ok, so I'm working with classes and its been a little while. I basically have to add a new private definition to a program I have already written and change the rest of the program to fit the new definition.
Here is the whole assignment for reference:http://cs.angelo.edu/~mmotl/2305/labs/lab02.pdf
Here is the private portion and the only thing I must add:

This was a program that I had already written and you can see that I changed all the instances that used to say numerator to r[0] and all the instances of denominator to r[1]. I don't know where I'm going wrong and why I'm getting that error. There are no tutors here right now either so any help would be appreciated.